1. Field of the Invention
The present invention relates to a braking system for hybrid vehicle and control method for the same. More particularly, the present invention relates to a braking system for hybrid vehicle and control method for the same which may realize regenerative braking and maintain brake feeling without a pedal simulator.
2. Description of Related Art
A cooperative control for regenerative braking system for a hybrid vehicle includes a simulator (BAU; Brake Actuation Unit) for generating a signal of driver's pedal operation and compensating operation feeling, and a control element (HPU; Hydraulic Power Unit) for controlling braking power of a brake.
When a driver pushes a brake pedal, a signal of a stroke sensor is generated and transmitted to the HPU, and the HPU generates brake hydraulic pressure according to the signal of the stroke sensor. Then the brake hydraulic pressure is applied to each brake of front and rear wheels through a wheel control unit simultaneously. The wheel control unit means an ABS (anti-lock braking system), a TCS (traction control system), an ESC (electric control suspension), an ESP (electronic stability control) and so on.
In braking of a vehicle, the HPU controls the brake hydraulic pressure to be closed for maximizing regenerative braking torque of a motor/generator at initial stage, and then the HPU controls the brake hydraulic pressure to be supplied in stopping regenerative braking or compensating braking force.
However, the regenerating system of the related art is complicated and reaction speed for braking is retarded. Also, with the pedal simulator, a driver may not satisfy brake feeling (pedal operation feeling).
Also, in the system, since the amplified pressure by the HPU is equally supplied to each brake of front and rear wheels, and thus the rear wheel brake (e.g., a driven wheel brake) may not be used in the cooperative regenerative braking controlling. So braking efficiency may be deteriorated and regenerative braking load is always applied to a front wheel (e.g., driving wheel) in braking. Thus, brake lock may occur to the front wheel so as to deteriorate braking performance, and durability of the front wheel brakes and tires may be deteriorated.
Also, since the system requires the BAU, the HPU and so on for the regenerative braking, weight and cost may be increased.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.